1. Field of the Invention
This invention relates to lubricant additives and to improved lubricant compositions and, in one of its aspects, relates more particularly to lubricant compositions which exhibit improved biocidal and anti-rust properties and also non-ferrous metal deactivation properties. Still more particularly, in this aspect, the invention relates to lubricant compositions in the form of oleagineous, aqueous and emulsion metal working fluids which are normally subject to one or more of the aforementioned characteristics of biocidal and rust formation, and also metal deterioration properties.
2. Description of the Prior Art
It is well-known that certain types of lubricants, including, for example, metal working fluids, are susceptible to microbial degradation, rust formation and other forms of metal deterioration in the course of performing their intended functions.
Various additive materials have been suggested by the prior art to overcome these shortcomings. Thus, U.S. Pat. No. 3,597,353, of Randell et.al., disclosed the use of 4,5,6,7-tetrahydrobenzotriazole as a metal deactivating additive for natural and synthetic lubricants. Similarly, U.S. Pat. No. 3,413,227 of Howard et.al. teaches that an alkyl-substituted benzotriazole containing an alkyl group of from 2 to 20 carbon atoms or an alkyanoylamine group containing from 3 to 20 carbon atoms can be used as corrosion or tarnish inhibitors.
Alkanolamines such as 2-amino-2-ethyl -1,3-propanediol, tertiary amines such as tri-n-butylamine, and alkali metal nitrites such as sodium nitrite are disclosed as rust inhibitors for soluble oil compositions in U.S. Pat. No. 3,201,349 of Quanstrom. U.S. Pat. No. 2,655,478 of Deutser et al. teaches that soluble oils can be inhibited against corrosion of steel by adding small amounts of an aliphatic alkylene polyamine having from 3 to 20 carbon atoms.
The above patents disclose the separate use of benzotriazoles or amines in lubricants as corrosion inhibitors. There is no teaching or suggestion of the present invention that a benzotriazole and a water soluble base react to form a product which exhibits improved biocidal properties. Indeed, the prior art cited above teaches that the incorporation of known bactericides is necessary to provide compositions with desired biocidal properties.
In U.S. Pat. No. 3,788,993 of Andress, it is taught that benzotriazoles react with alkyl or alkenyl succinic anhydrides to form reaction products which impart corrosion inhibiting the properties to lubricating oils. Such disclosure of the reaction of benzotriazole with an acid (or anhydride) highlights the difference between the prior art reactions and those of the present invention, where benzotriazole is reacted with a basic material. The significance of such differences will be discussed in greater detail hereinafter. British Pat. No. 995,708 discloses an aqueous metal working fluid which comprises an aqueous solution containing a polyoxyalkylene glycol, as well as salt of an alkanolamine and a dibasic carboxylic acid. It also discloses that small amounts of benzotriazole can also be included in the fluid as a metal deactivator. The lack of biocidal properties exhibited by the fluids of this patent is evident from specific disclosure directed to the desirability of adding bactercides. U.S. Pat. No. 3,374,171 of Davis also teaches the failure of compositions similar to those of the British Patent in exhibiting biocidal properties.
Finally, U.S. Pat. No. 3,265,620 of Heiman, describes a concentrate of triethanolamine, sodium nitrite, and a small amount of benzotriazole to which an amino polycarboxylic acid chelating agent is preferably added. As those skilled in the art are aware, the presence of sodium nitrite would contribute to, rather than inhibit, the growth of bacteria.
Thus, the prior art discloses products which are different than the reaction products of the present invention and which do not exhibit the biocidal properties of the novel reaction product described and claimed herein.